This invention relates to a vertical sump pump motor and particularly to a sump pump motor releasably interconnected to a bottom pump unit for operation in a liquid collection sump or well.
In dwellings and other building structures having basements, water accumulates around the base structure. Drainage systems are installed to direct the water into a well or sump formed in the basement floor. Motor-driven sump pump units are mounted in the sump with an appropriate inlet and an outlet pipe system for draining the water to a waste disposal, generally to the exterior of the building structure or to a common sewage collection system. A widely used motor-driven pump unit includes a lower disc-like pump structure adapted to rest on the floor of the sump. The housing includes an impeller and a bottom opening for sucking of the water into and through the pump unit to a vertical discharge pipe or hose. A central pedestal pipe projects upwardly, with a pump impeller shaft extending therethrough. An electric motor is mounted to the upper end of the pedestal pipe with a motor shaft fixedly coupled to the pump shaft. The motor is thus supported above the level of the accumulating water in the sump. Automated pumping is established with a conventional switch unit through a float responsive control. In one such system, a rod member is secured, generally to the supporting pedestal structure and the motor by suitable brackets to support the rod spaced outwardly of the motor. A float member is slidably disposed on the rod. A first switch actuator is located at a lower portion of the rod to support the float in spaced relation to the pump unit with the sump empty. A second switch actuator is coupled to the rod adjacent the upper portion thereof and spaced from the first switch actuator by a distance corresponding to the accumulated water in the sump at a selected maximum level. As the water accumulates in the sump, the float rises and at the maximum level engages and actuates the switch unit. The actuation of the switch unit energizes the motor to pump the water from the sump to the waste or disposal location. The float drops with the level of the discharged water. The motor operates until the water level drops to the lower level, generally corresponding to an essentially empty sump, and the float actuates the first switch actuator to turn off the motor. Motors are generally specially constructed to operate in the environment of the sump, with the motor frame specially constructed for mounting to the pump unit and with a closed construction adapting the motor for sump pump operation.
The standard pump motor generally includes a special start winding which is selectively connected in circuit during the starting of the motor and is automatically disconnected from the motor circuit as the motor reaches or approaches normal operating speed. A centrifugal governor or actuator unit is mounted as an integrated part within the motor for centrifugal actuation of a mechanical switch as the motor approaches the desired running speed such that the motor continues to operate thereafter with only the run winding energized.
The present inventors realized that the sump motors could advantageously be constructed using a standard fractional horsepower motor widely used in various appliance and other applications. Such mass produced motors provide a most economical motor construction, and fabrication process, and have a more substantial size; giving an impression of a more substantial and powerful motor than that generally supplied with a conventional sump pump unit. The fractional horsepower motors however are generally constructed with the usual ground main frame, generally using a standard No. 48 frame, with end closure members such as closure or bearing frames and with the shaft projecting from one end. Mass produced fractional horsepower motors for various applications, appliances and the like may be constructed with two phase windings including a start winding and a run winding. The motor start with energizing of both windings and the motor control often includes a current sensitive relay to open the circuit to one phase after the motor approaches or reaches the running speed. The standard motor is not constructed for mounting to a sump pump unit, and particularly may not include a centrifugal switch or governor structure. Although the end frame structures could be specially constructed in accordance with the conventional sump pump motors, the advantages associated with mass production and the attendant cost factor would be minimized. The inventors realize therefore that there is a need for a special construction for fractional horsepower motors which adapts them to a sump pump application while maintaining the economy of construction associated with the standard fractional horsepower motors.